i gtta 99 GTP transmission will start shuddering when trying to hold at acertain speed shifts fine no delays atall n between shifts only acts up when u just try to cruise i changed out the Trottlebody Position Sensor,new tranny fluid&filter and cleaned out the trottlebody lightweight but still got this shudder for sum reason can sum1 please give me an opinion on what it could be???im thinkin it might be the speed sensor but not sure ......